Grain sized fossil helps unspool climate change mystery

November 9th, 2009 - 5:30 pm ICT by IANS  

Washington, Nov 9 (IANS) Deep under the sea, a sand grain sized fossil nestles among a billion of its closest dead kins. Known as foraminifera, these complex little shells of calcium carbonate can tell you the sea level, temperature, and ocean conditions of Earth millions of years ago — that is, if you know what to look for.
Miriam Katz, assistant professor of earth and environmental sciences at Rensselaer Polytechnic Institute (RPI) has spent the past two decades studying these ancient, deep-sea fossils to reconstruct the climates up to 250 million years ago.

Through ice ages and greenhouse climates, Katz has been able to piece together oxygen, carbon, and faunal data to paint a portrait of how, when, and why our climate has changed so drastically over geologic history.

“There is a saying among scientists in my field that ‘the past is a window on the future’,” Katz said.

While her work requires a lot of time in the lab, Katz has spent nearly two years at sea on seven different ocean voyages around the world to drill for foraminifera as part of the Integrated Ocean Drilling Program (IODP).

During each two-month IODP excursion, Katz and the other scientists on board never set foot on land and spend hours poking through the millions of layers of sediment, trapped gases, fossils, and trace elements found in huge cores drilled from deep under the seafloor.

Just a few inches in diameter, each core is painstakingly drilled and removed from the seafloor. From top to bottom, the core provides a reverse chronology of the various organisms, sediments, and elements that were found on earth throughout history.

Unlike cores from sedimentary layers from the continents that are quickly destroyed by the forces of plate tectonics, wind, and water, these rarely disturbed ocean sediment cores can provide records up to 180 million years ago as new layers of sediment bury and preserve those of the past.

The assemblages of foraminifera in each layer can provide valuable information on the climate of that time, according to a Rensselaer release.

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